Decision Feedback Equalizer with Embedded Coherent Signal Combiner

1. A decision feedback equalizer for combining the significant component signals of a multipath-fading signal together and eliminating all the other component signals, comprising: a first filter, which is coupled to receive a first combined signal, for eliminating the interference of future samples to the sample under consideration; a second filter, which is coupled to receive a second combined signal, for eliminating the interference of past samples to the sample under consideration; a first delay device for producing a delayed signal by delaying its input signal for a certain amount of time so that said delayed signal can align up with the signals from said first filter; a summation circuit for combining the signals from said first delay device, said first filter, and said second filter to produce a modified signal; a signal generator, which is coupled to receive signal from said summation circuit, for exacting information about each significant component signal of said modified signal and producing said second combined signal; a second delay device, for delaying said modified signal from said summation circuit for a certain amount of time so that its output signal can align up with the said second combined signal from said signal generator; and a coefficient updating device, which is coupled to receive signals from said second delay device and said signal generator, for producing adjusting signals to update the coefficients in said first filter and said second filter.

2. A decision feedback equalizer for combining the significant component signals of a multipath fading signal together and eliminating all the other component signals as in claim 1 , wherein said first combined signal is generated by a signal generator.

3. A decision feedback equalizer for combining the significant component signals of a multipath-fading signal together and eliminating all the other component signals as in claim 1 , wherein a signal generator comprises: a plurality of information extractors, each for exacting the information about a significant component signal from its input signal respectively; a coherent signal combiner for combining the significant component signals of its input signal coherently to produce a revised signal; a decision circuit, which is coupled to receive said revised signal from said coherent signal combiner, for making tentative decisions on transmitted symbols; a plurality of component signal generators, each of which is coupled to said decision circuit and a corresponding information extractor, each for rebuilding a corresponding significant component signal; and a summation circuit, which is coupled to receive rebuilt signals from said a plurality of component signal generators, for adding these rebuilt significant component signals together to produce a combined signal.

4. A decision feedback equalizer for combining the significant component signals of a multipath-fading signal together and eliminating all the other component signals as in claim 1 , wherein a signal generator comprises: a plurality of information extractors, each for exacting the information about a significant component signal from its input signal respectively; a plurality of demodulators, each for demodulating a significant component signal of its input signal respectively; a plurality of component signal generators, each of which is coupled to a corresponding demodulator and a corresponding information extractor, each for rebuilding a corresponding significant component signal; and a summation circuit, which is coupled to receive rebuilt signals from said a plurality of component signal generators, for adding these rebuilt significant component signals together to produce a combined signal.

5. A subsystem for combining all the significant component signals of a multipath-fading signal together and eliminating all the other component signals, comprising: a plurality of first delay devices, one of which is coupled to the received signal and each of the rest of which is coupled to its previous delay device, each for producing a delayed signal by delaying its input signal for a certain amount of time; a signal generator, coupled to the received signal, for exacting information about each of the significant component signals, rebuilding these significant component signals, and adding these signals together to produce a combined signal; a plurality of decision feedback equalizers, one of which is coupled to receive signal from said signal generator and each of rest of which is coupled to receive signal from its previous decision feedback equalizer, each for eliminating the interference of future samples and past samples to the sample under consideration and producing a combined signal; a coherent signal combiner, which is coupled to receive signal from of the summation circuit of the last decision feedback equalizer, for combining the significant component signals of its input signal together; a decision circuit, which is coupled to receive signal from said coherent signal combiner, for making a decision on transmitted symbol; and a controller for extracting information from various devices and producing necessary control signals for the relevant devices.

6. A subsystem for combining all the significant component signals of a multipath fading signal together and eliminating all the other component signals in claim 5 , wherein a plurality of decision feedback equalizers, each of which comprises: a first filter, receiving a combined signal from a signal generator, for eliminating the interference of future samples to the sample under consideration; a second filter, receiving a combined signal from another signal generator, for eliminating the interference of past samples to the sample under consideration; a summation circuit for combining the signals from a corresponding first delay device, said first filter, and said second filter to produce a modified signal; a signal generator for exacting information from said modified signal and producing a combined signal; a second delay device, which is coupled to receive the modified signal from said summation circuit, for delaying its input signal for a certain amount of time; and a coefficient-updating device, which is coupled to receive signals from said second delay device and said signal generator, for producing adjusting signals to update the coefficients in both said first filter and said second filter.

7. A subsystem for combining all the significant component signals of a multipath fading signal together and eliminating all the other component signals as in claim 6 , wherein a signal generator comprises: a plurality of information extractors, each for exacting the information about a corresponding significant component signal from its input signal; a coherent signal combiner for combining all the significant component signals together coherently to produce a revised signal; a decision circuit, which is coupled to receive said revised signal from said coherent signal combiner, for making tentative decisions on transmitted symbols; a plurality of component signal generators, each of which is coupled to said decision circuit and a corresponding information extractor, each for rebuilding a corresponding significant component signal; and a summation circuit, which is coupled to receive rebuilt signals from said a plurality of component signal generators, for adding these rebuilt significant component signals together to produce a combined signal.

8. A subsystem for combining all the significant component signals of a multipath fading signal together and eliminating all the other component signals as in claim 6 , wherein a signal generator comprises: a plurality of information extractors, each for exacting the information about a significant component signal from its input signal; a plurality of demodulators, each for demodulating a corresponding significant component signal; a plurality of component signal generators, each of which is coupled to a corresponding demodulator and a corresponding information extractor, for rebuilding a corresponding significant component signal; and a summation circuit, which is coupled to receive rebuilt signals from said a plurality of component signal generators, for adding these rebuilt significant component signals together to produce a combined signal.

9. A subsystem for combining the significant component signals of a multipath fading signal together and eliminating all the other component signals of the multipath fading signal, comprising: a coherent signal combiner for combining the significant component signals of the multipath fading signal together to produce a revised signal; a first decision circuit, which is coupled to receive signal from said coherent signal combiner, for making tentative decisions on transmitted symbols; a first signal generator, which is coupled to receive signals from said coherent signal combiner and said first decision circuit, for producing a signal with only one component signal and with signal strength proportional to the signal strength of said revised signal; a first filter, which is coupled to receive signal from said first signal generator, for estimating the precursor interference of future samples to the sample under consideration; a first delay device, which is coupled to receive signal from said coherent signal combiner, for delaying its input signal by a certain amount of time so that its output signal can align up with the signals from said first filter; a second filter, which is coupled to a second signal generator, for estimating the postcursor interference of past samples to the sample under consideration; a summation circuit, which is coupled to receive signals from said first delay device, said first filter, and said second filer, for adding these signals together; a second decision circuit, which is coupled to receive signal from said summation circuit, for making decisions on transmitted symbols; a second signal generator, which is coupled to receive signal from said second decision circuit and said summation circuit, for producing a signal with only one component signal and with signal strength proportional to the signal strength of the signal from said summation circuit for said second filter; and a coefficient updating device, for producing adjusting signals to update the coefficients of both said first filter and said second filter.

10. A subsystem for combining the significant component signals of a multipath fading signal together and eliminating all the other component signals of the multipath fading signal as in claim 9 , further comprising: a second delay device, which is coupled to receive signal from said summation circuit, for delaying its input signal by a certain amount of time so that its output signal can align up with the signal from said second signal generator, whereby said coefficient updating device is coupled to receive signals from said second delay device and said second signal generator to producing adjusting signals.